Mac Mini

A photo of the rear of the refreshed Mac Mini and specs were first posted in late February 2009, about a week before the refreshed Mac Mini's release to the Mac Rumors forums and were deemed by many to be fake. Discussion thread The next day, a video featuring the refreshed Mini being spun around which appeared related to the first picture was released and caused much discussion about the validity of the featured Mac Mini. Discussion thread

Mac Mini Rear

A few days later, another photo, this time of the box of the refreshed Mac Mini was sent to MacRumors and many other rumor sites. It was originally deemed as a fake and posted to Page 2, however, OneMoreThing.nl believed the photo to be real, and it was subsequently posted as a Page 1 rumor. Like the previous images, many questioned this image's validity. Discussion thread The next day the refreshed Mac Mini was released featuring specs the same as leaked ones.

Mac Pro 8-core

The 8-core Mac Pro was leaked on Apple's UK website, when searching Mac Pro on the site it showed these results:

Screen shot of the slip-up

The little slip-up on the site was removed within hours. The rumors happened to be true, and the 8-core Mac Pro was introduced in a few weeks. The article is discussed here: MacRumors Discussion of the slip-up

iLife '06 with iWeb

Jan 5, 2006. A slip-up on Apple's website revealed a few details of their annual iLife update, confirming its updated title (iLife '06) and a new program called "iWeb". Apple changed the website within hours, but enough people had got a glimpse of the page to start speculation and discussion over its new features.

4G "Clickwheel" iPod

PowerMac G5 Specs

Apple accidentally leaked the specs for the PowerMac G5 on July 19th 2003 on their own website. The news quickly spread across the Mac web. The specs for the then unreleased PowerMac G5 were indeed true. The PowerMac G5 was introduced at WWDC 2003. Steve Jobs acknowledged the leak during his Keynote speech. Here's the original screenshot posted, and the original discussion thread:

Screenshot of Apple site. Top Left block of specs were accidentally posted prematurely.

PowerMac G4

These images were leaked on July 22, 2002. The images depict a new PowerMac G4 design and photos of the motherboard along with some specs. A PDF diagram was posted to the MacRumors forums, and these images later posted on MacBidouille.